Single inductor fully integrated differential voltage controlled oscillator with automatic amplitude adjustment and on-chip varactor

Abstract

The voltage controlled oscillator (VCO) of the present invention generally includes a energy storage circuit portion, an oscillator operably connected to the energy storage circuit portion, a varactor connected to the oscillator and energy storage circuit portion, and an amplitude controller that is operably connected to the energy storage circuit portion, oscillator, and varactor. The energy storage circuit portion includes an inductance and a capacitance. The oscillator provides an oscillating output signal having a frequency and an amplitude. The varactor has a capacitance and receives an input signal having a varying level. The capacitance of the varactor varies according to the level of the input signal. The amplitude controller sets the amplitude of the oscillating output signal. Meanwhile, the inductance of the energy storage circuit portion, the capacitance of the energy storage circuit portion, and the varying capacitance of the varactor are used to set the frequency of the oscillating output signal. The VCO of the present invention is preferably fabricated entirely on a single integrated circuit chip utilizing low-cost CMOS technology.

What is claimed:  
     
       1. A voltage controlled oscillator (VCO) for use in communication systems, comprising: 
       an energy storage circuit portion having an inductance and a capacitance;  
       an oscillator providing an oscillating output signal having a frequency and an amplitude, wherein said oscillator is operably connected to said energy storage circuit portion;  
       a varactor having a capacitance, wherein said varactor is operably connected to said energy storage circuit portion ad said oscillator, wherein said varactor receives an input signal having a varying level, and wherein said capacitance of said varactor varies according to said varying level of said input signal;  
       an amplitude controller including a first current mirror and a second current mirror operably connected to said energy storage circuit portion, said oscillator, and said varactor, wherein said amplitude controller initiates the oscillation of said oscillator and sets said amplitude of said oscillating output signal; and  
       wherein said varactor comprises at least one MOSFET.  
     
     
       2. The VCO of claim  1 , wherein said inductance of said energy storage circuit portion, said capacitance of said energy storage circuit portion, and said capacitance of said varactor determine said frequency of said oscillating output signal. 
     
     
       3. A voltage controlled oscillator (VCO) for use in communication systems, comprising: 
       an energy storage circuit portion having an inductance and a capacitance;  
       an oscillator providing an oscillating output signal having a frequency and an amplitude, wherein said oscillator is operably connected to said energy storage circuit portion;  
       a varactor having a capacitance, wherein said varactor is operably connected to said energy storage circuit portion and said oscillator, wherein said varactor receives an input signal having a varying level, and wherein said capacitance of said varactor varies according to said varying level of said input signal;  
       an amplitude controller including a first current mirror and a second current mirror operably connected to said energy storage circuit portion, said oscillator, and said varactor, wherein said amplitude controller initiates the oscillation of said oscillator and sets said amplitude of said oscillating output signal; and  
       wherein said voltage controlled oscillator is fabricated entirely with CMOS technology.  
     
     
       4. The VCO of claim  3 , wherein said inductance of said energy storage circuit portion, said capacitance of said energy storage circuit portion, and said capacitance of said varactor determine said frequency of said oscillating output signal. 
     
     
       5. A voltage controlled oscillator (VCO) for use in communication systems, comprising: 
       an energy storage circuit portion having an inductance and a capacitance;  
       an oscillator providing an oscillating output signal having a frequency and an amplitude, wherein said oscillator is operably connected to said energy storage circuit portion;  
       a varactor having a capacitance, wherein said varactor is operably connected to said energy storage circuit portion and said oscillator, wherein said varactor receives an input signal having a varying level, and wherein said capacitance of said varactor varies according to said varying level of said input signal;  
       an amplitude controller including a first current mirror and a second current mirror operably connected to said energy storage circuit portion, said oscillator, and said varactor, wherein said amplitude controller initiates the oscillation of said oscillator and sets said amplitude of said oscillating output signal; and  
       wherein said energy storage circuit portion comprises an inductor and a capacitor, and wherein said capacitor of said energy storage circuit portion, said oscillator, said varactor, and said amplitude controller are fabricated entirely on-chip with CMOS technology and wherein said inductor of said energy storage circuit portion is located off-chip.  
     
     
       6. The VCO of claim  5 , wherein said inductance of said energy storage circuit portion, said capacitance of said energy storage circuit portion, and said capacitance of said varactor determine said frequency of said oscillating output signal. 
     
     
       7. A voltage controlled oscillator (VCO) for use in communication systems, comprising: 
       an energy storage circuit portion having an inductance and a capacitance;  
       a oscillator providing an oscillating output signal having a frequency and an amplitude, wherein said oscillator is operably connected to said energy storage circuit portion;  
       a varactor having a capacitance, wherein said varactor is operably connected to said energy storage circuit portion and said oscillator, wherein said varactor receives an input signal having a varying level, and wherein said capacitance of said varactor varies according to said varying level of said input signal;  
       an amplitude controller including a first current mirror and a second current mirror operably connected to said energy storage circuit portion, said oscillator, and said varactor, wherein said amplitude controller initiates the oscillation of said oscillator and sets said amplitude of said oscillating output signal; and  
       wherein said oscillator provides a balanced, differential, oscillating output signal.  
     
     
       8. The VCO of claim  7 , wherein said inductance of said energy storage circuit portion, said capacitance of said energy storage circuit portion, and said capacitance of said varactor determine said frequency of said oscillating output signal. 
     
     
       9. A voltage controlled oscillator (VCO) for use in communication systems, comprising: 
       an energy storage circuit portion having an inductance and a capacitance;  
       an oscillator providing an oscillating output signal having a frequency and an amplitude, wherein said oscillator is operably connected to said energy storage circuit portion;  
       a varactor having a capacitance, wherein said varactor is operably connected to said energy storage circuit portion and said oscillator, wherein said varactor receives an input signal having a varying level, and wherein said capacitance of said varactor varies according to said varying level of said input signal;  
       an amplitude controller including a first current mirror and a second current mirror operably connected to said energy storage circuit portion, said oscillator, and said varactor, wherein said amplitude controller initiates the oscillation of said oscillator and sets said amplitude of said oscillating output signal; and  
       wherein said amplitude controller provides automatic, closed-loop adjustment of said amplitude of said oscillating output signal.  
     
     
       10. The VCO of claim  9 , wherein said inductance of said energy storage circuit portion, said capacitance of said energy storage circuit portion, and said capacitance of said varactor determine said frequency of said oscillating output signal. 
     
     
       11. A voltage controlled oscillator (VCO) for use in communication systems comprising: 
       energy storage means for providing an inductance and a capacitance;  
       oscillating means for providing an oscillating output signal having an amplitude and a frequency, wherein said oscillating means is operably connected to said energy storage means;  
       variable capacitance means for providing a variable capacitance, wherein said variable capacitance means is operably connected to said energy storage circuit portion means and said oscillating means, wherein said variable capacitance means receives an input signal having a varying level, and wherein said variable capacitance varies according to said varying level of said input signal;  
       amplitude control means including a fist current mirror and a second current mirror operably connected to said energy storage means, said oscillating means and said variable capacitance means for initiating oscillation of said oscillating means and controlling said amplitude of said output signal; and  
       wherein said variable capacitance means comprises at least one MOSFET.  
     
     
       12. The VCO of claim  11 , wherein said inductance of said energy storage means, said capacitance of said energy storage means, and said variable capacitance of said variable capacitance means determine said frequency of said oscillating output signal. 
     
     
       13. A voltage controlled oscillator (VCO) for use in communication systems comprising: 
       energy storage means for providing an inductance and a capacitance;  
       oscillating means for providing an oscillating output signal having an amplitude and a frequency, wherein said oscillating means is operably connected to said energy storage means;  
       variable capacitance means for providing a variable capacitance, wherein said variable capacitance means is operably connected to said energy storage circuit portion means and said oscillating means, wherein said variable capacitance means receives an input signal having a varying level, and wherein said variable capacitance varies according to said varying level of said input signal;  
       amplitude control means including a fist current minor and a second current mirror operably connected to said energy storage means, said oscillating means and said variable capacitance means for initiating oscillation of said oscillating means and controlling said amplitude of said output signal; and  
       wherein in said voltage controlled oscillator is fabricated entirely with CMOS technology.  
     
     
       14. The VCO of claim  13 , wherein said inductance of said energy storage means, said capacitance of said energy storage means, and said variable capacitance of said variable capacitance means determine said frequency of said oscillating output signal. 
     
     
       15. A voltage controlled oscillator (VCO) for use in communication systems comprising: 
       energy storage means for providing an inductance and a capacitance;  
       oscillating means for providing an oscillating output signal having an amplitude and a frequency, wherein said oscillating means is operably connected to said energy storage means;  
       variable capacitance means for providing a variable capacitance, wherein said variable capacitance means is operably connected to said energy storage circuit portion means and said oscillating means, wherein said variable capacitance means receives an input signal having a varying level, and wherein said variable capacitance varies according to said varying level of said input signal;  
       amplitude control means including a first current mirror and a second current mirror operably connected to said energy storage means, said oscillating means and said variable capacitance means for initiating oscillation of said oscillating means and controlling said amplitude of said output signal; and  
       wherein said energy storage means comprises an inductor and a capacitor, and wherein said capacitor of said energy storage means, said oscillating means, said variable capacitance means, and said amplitude control means are fabricated entirely on-chip with CMOS technology and wherein said inductor of said energy storage means is located off-chip.  
     
     
       16. The VCO of claim  15 , wherein said inductance of said energy storage means, said capacitance of said energy storage means, and said variable capacitance of said variable capacitance means determine said frequency of said oscillating output signal. 
     
     
       17. A voltage controlled oscillator (VCO) for use in communication systems comprising: 
       energy storage means for providing an inductance and a capacitance;  
       oscillating means for providing an oscillating output signal having an amplitude and a frequency, wherein said oscillating means is operably connected to said energy storage means;  
       variable capacitance means for providing a variable capacitance, wherein said variable capacitance means is operably connected to said energy storage circuit portion means and said oscillating means, wherein said variable capacitance means receives all input signal having a vying level, and wherein said variable capacitance varies according to said varying level of said input signal;  
       amplitude control means including a first current minor and a second current mirror operably connected to said energy storage means, said oscillating means and said variable capacitance means for initiating oscillation of said oscillating means and controlling said amplitude of said output signal; and  
       wherein said oscillating means provides a balanced, differential, oscillating output signal.  
     
     
       18. The VCO of claim  17 , wherein said inductance of said energy storage means, said capacitance of said energy storage means, and said variable capacitance of said variable capacitance means determine said frequency of said oscillating output signal. 
     
     
       19. A voltage controlled oscillator (VCO) for use in communication systems comprising: 
       energy storage means for providing an inductance and a capacitance;  
       oscillating means for providing an oscillating output signal having an amplitude and a frequency, wherein said oscillating means is operably connected to said energy storage means;  
       variable capacitance means for providing a variable capacitance, wherein said variable capacitance means is operably connected to said energy storage circuit portion means and said oscillating means, wherein said variable capacitance means receives an input signal having a varying level, and wherein said variable capacitance varies according to said varying level of said input signal;  
       amplitude control means including a first current mirror and a second current mirror operably connected to said energy storage means, said oscillating means and said variable capacitance means for initiating oscillation of said oscillating means and controlling said amplitude of said output signal; and  
       wherein said amplitude control means provides automatic, closed-loop adjustment of said amplitude of said oscillating output signal.  
     
     
       20. The VCO of claim  19 , wherein said inductance of said energy storage means, said capacitance of said energy storage means, and said variable capacitance of said variable capacitance means determine said frequency of said oscillating output signal. 
     
     
       21. A method of adjusting the frequency and amplitude of an oscillating output signal, comprising the steps of: 
       receiving an input signal having a varying level;  
       varying a capacitance of a varactor according to said varying level of said input signal;  
       adjusting the frequency of an oscillator according to said capacitance of said varactor to provide an oscillator output signal;  
       providing current conduction for amplitude control upon an energy storage circuit portion reaching or exceeding a peak level;  
       continuing to provide current conduction to stabilize said amplitude; and  
       adjusting current to achieve a desired amplitude after said amplitude is stabilized.  
     
     
       22. The method of claim  21 , wherein said varactor comprises at least one MOSFET. 
     
     
       23. The method of claim  21 , further comprising the step of continuously adjusting the current in a closed-loop fashion to maintain said desired amplitude. 
     
     
       24. A voltage controlled oscillator (VCO) for use in communication systems, comprising: 
       an energy storage circuit portion having an inductance and a capacitance;  
       an oscillator providing an oscillating output signal having a frequency and an amplitude, wherein said oscillator is operably connected to said energy storage circuit portion;  
       a varactor having a capacitance, wherein said varactor is operably connected to said energy storage circuit portion and said oscillator, wherein said varactor receives an input signal having a varying level, and wherein said capacitance of said varactor varies according to said varying level of said input signal; and  
       an amplitude controller including a first current mirror and a second current mirror operably connected to said energy storage circuit portion, said oscillator, and said varactor, wherein said amplitude controller initiates the oscillation of said oscillator and sets said amplitude of said oscillating output signal; and  
       wherein said capacitor of said energy storage circuit portion, said oscillator, said varactor, and said amplitude controller are fabricated entirely on-chip with CMOS technology and wherein said inductor of said energy storage circuit portion is located off-chip.  
     
     
       25. The VCO of claim  24 , wherein said inductance of said energy storage circuit portion, said capacitance of said energy storage circuit portion, and said capacitance of said varactor determine said frequency of said oscillating output signal. 
     
     
       26. The VCO of claim  24 , wherein said varactor comprises at least one MOSFET. 
     
     
       27. The VCO of claim  24 , wherein said voltage controlled oscillator is fabricated entirely with CMOS technology. 
     
     
       28. The VCO of claim  24 , wherein said oscillator provides a balanced, differential, oscillating output signal. 
     
     
       29. The VCO of claim  24 , wherein said amplitude controller provides automatic, closed-loop adjustment of said amplitude of said oscillating output signal. 
     
     
       30. A voltage controlled oscillator (VCO) for use in communication systems comprising: 
       energy storage means for providing an inductance and a capacitance;  
       oscillating means for providing an oscillating output signal having an amplitude and a frequency, wherein said oscillating means is operably connected to said energy storage means;  
       variable capacitance means for providing a variable capacitance, wherein said variable capacitance means is operably connected to said energy storage circuit portion means and said oscillating means, wherein said variable capacitance means receives an input signal having a varying level, and wherein said variable capacitance varies according to said varying level of said input signal;  
       amplitude control means including a first current mirror and a second current mirror operably connected to said energy storage means, said oscillating means and said variable capacitance means for initiating oscillation of said oscillating means and controlling said amplitude of said output signal; and  
       wherein said capacitor of said energy storage means, said oscillating means, said variable capacitance means, and said amplitude control means are fabricated entirely on-chip with CMOS technology and wherein said inductor of said energy storage means is located off-chip.  
     
     
       31. The VCO of claim  30 , wherein said inductance of said energy storage means, said capacitance of said energy storage means, and said variable capacitance of said variable capacitance means determine said frequency of said oscillating output signal. 
     
     
       32. The VCO of claim  30 , wherein said variable capacitance means comprises at least one MOSFET. 
     
     
       33. The VCO of claim  30 , wherein in said voltage controlled oscillator is fabricated entirely with CMOS technology. 
     
     
       34. The VCO of claim  30 , wherein said oscillating means provides a balanced, differential, oscillating output signal. 
     
     
       35. The VCO of claim  30 , wherein said amplitude control means provides automatic, closed-loop adjustment of said amplitude of said oscillating output signal.